SOLUTION: Jack usually mows his lawn in 5 hours. Marilyn can mow the same yard in 3 hours. How much time would it take for them to mow the yard together?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Jack usually mows his lawn in 5 hours. Marilyn can mow the same yard in 3 hours. How much time would it take for them to mow the yard together?      Log On


   

Question 474238: Jack usually mows his lawn in 5 hours. Marilyn can mow the same yard in 3 hours. How much time would it take for them to mow the yard together?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let t = time to mow 1 lawn working together
Add their rates of working
Jack's rate:
1 lawn mowed / 5 hours
Marilyn's rate:
1 lawn mowed / 3 hours
Rate working together = +1%2F5+%2B+1%2F3+
Rate working together = +3%2F15+%2B+5%2F15+=+8%2F15+
+8%2F15+=+1%2Ft+
+t+=+15%2F8+
+t+=+1.875+ hrs
Time - 1 hr + +.875%2A60+=+52.5+ min
It takes them 1 hr and 52.5 min working together